This application is based on and claims the benefit of priority of Japanese Patent Application No. 2001-276064 filed on Sep. 12, 2001, the disclosure of which is incorporated herein by reference.
The present invention relates to a wiper device for a vehicle for wiping a window glass surface of the vehicle.
In a vehicular wiper device for wiping a windshield, a wiper blade is generally pressed against the windshield by an arm pressure of a wiper arm for a long time while the wiper device is turned off. As a result, a blade rubber is likely to be deformed. For example, a wiper device disclosed in JP-A-2000-289577 has a mechanism for lifting up a wiper blade to suppress the deformation of the blade rubber.
In a wiper device having such a lifting mechanism, a sliding unit is fixed to a wiper blade rotatably held on a wiper arm through a holding axis. A lifter is attached on a vehicle body adjacent to a wiper blade""s stationary position. When the wiper device is turned off and the wiper blade is returned to the stationary position, the sliding unit is mounted on the lifter so that the wiper blade is lifted. In this way, the deformation of the blade rubber is decreased.
In this kind of lifting mechanism, a rivet or screw is required to fix the sliding unit to the wiper blade. In addition, the lifted wiper blade is likely to rotate about the holding axis due to vibration of the vehicle, especially, while the vehicle is running over bad roads. As a result, ends of the wiper blades contact the vehicle body, thereby causing rattling noises.
To suppress the rattling noises, for example, a wiper blade is held with an E-clip fixed at the end of a wiper arm. Further, a Z-shaped plate spring stopper is placed between the E-clip and the wiper blade so that a rotation of the wiper blade is restricted with a biasing force of the plate spring stopper. As another example, the wiper blade is held in a state that the wiper blade is positively in contact with the wiper arm while being lifted to prevent the wiper blade from rotating.
In the above wiper devices, however, additional parts such as the E-clip and the plate spring stopper are required to hold the wiper blade. With this, the number of parts and assembling steps are increased, resulting in an increase of a manufacturing cost. Further, in a case that the sliding unit fixed on the wiper blade is exposed largely, an external appearance is lessened.
The present invention is made in view of the above disadvantages and an object of the present invention is to provide a wiper device for vehicles in which a wiper blade is lifted without vibrating to suppress rattling noises.
Another object of the present invention is to provide a wiper device with an enhanced appearance.
Further another object of the present invention is to provide a wiper device in which the number of parts is reduced and an assembling workability is improved.
In a wiper device of the present invention, a wiper blade is rotatably held at an end of a wiper arm through a holding axis. The wiper arm has a longitudinal base wall and a first and second side walls extending from longitudinal edges of the base wall, so that the wiper arm has substantially a U-shaped cavity opening toward a wiping surface. The wiper blade is pressed toward the wiping surface with an arm pressure exerted from the wiper arm. The wiper blade reciprocates with a rotation of the wiper arm and wipes the wiping surface. A slider is provided on the wiper blade at a position being shifted from the holding axis toward the wiper arm. A slider base of the slider and a portion of the wiper blade having the slider base are provided to be retractable in the cavity. A sliding protrusion of the slider protrudes toward a wiper blade""s stationary position.
When the wiper device is turned off and the wiper blade is returned to the stationary position, the sliding protrusion runs onto a lifter mounted on the vehicle so that the wiper blade is lifted in a direction separating from the wiping surface.
According to the wiper device, since the slider is provided on the wiper blade at a position being shifted toward the wiper arm from the holding axis, when the wiper blade is lifted, a rotational force about the holding axis is generated on the wiper blade. At this time, the slider base and the portion of the wiper blade having the slider base are moved toward an inner surface of the base wall of the wiper arm. The wiper blade contacts with the wiper arm at a point different from the holding axis.
Since the arm pressure is applied to the wiper arm, the wiper blade is pressed against the lifter through the contact point. With this, the wiper blade is held in a state that the rotation about the holding axis is limited at the contact point. Accordingly, even when a blade rubber of the wiper blade is completely separated from the wiping surface, the wiper blade is securely held against the wiper arm without vibrating, thereby suppressing rattling noises.
Further, when the wiper blade is lifted, that is, when the slider base and the portion of the wiper blade having the slider base are moved toward the base wall with the rotational force about the holding axis, the slider base and the portion of the wiper blade having the slider base are retracted in the cavity. Therefore, an external appearance of the wiper device is improved.